1. Field of Invention
The present invention relates to an automotive relay, in particular, to a sealing type automotive relay with a safety device.
2. Related Art
Automotive relays are mainly used to control switch of large currents, and could only work stably and reliably where an overload protection is available when the current is overloaded. There is no safety device in the strong current switching circuit in the existing automotive relays. The automotive relays have a small volume and the switch circuits are large, and the automotive relays have to stand vibration and high temperature, for which the space is insufficient where a safety device has to be loaded. Therefore, it is difficult to add a safety device to the automotive relays. If the volume of the automotive relay is to be increased, a fuse has to be added to the relay, which is unacceptable in new automotives.
In order to improve the quality of automotive relays and meet technical requirements for the product to be used in different environments, some technical measures are employed. For example, a safety device is provided next to the main body of the automotive relay and a connection element is used for connection. However, the volume and contact resistance of the automotive relay will be increased as such. Consequently, the reliability of the product can not be guaranteed and the problem that the product has a relatively large volume can not be efficiently addressed.
In order to address the problems as mentioned above, an automotive relay with a safety device is disclosed in a patent No. 200810164226.X, the publication number of which is CN101459015A. The automotive replay comprises a relay main body and a safety device. The relay main body includes a weak current system, a strong current system, a base and a casing. The weak current system includes an iron core, a coil, a yoke iron, an armature and an armature compression spring. The safety device includes two fuse sockets and a fuse inserted between two fuse sockets. The upper part of one fuse socket is a plug connector and the lower part hereof is a stationary article in which the stationary article is fixed on the yoke iron. The upper part of the other fuse socket is a plug connector in which an insulation spacer is provided between the plug connector and the yoke iron, and the lower part thereof has a power supply pin and a stationary pin in which the power supply pin passes through the base and the position thereof then is restricted on the base and the stationary pin is inserted onto the base. The top of the casing is provided with a fuse inserting hole corresponding to two fuse sockets, into which the fuse is inserted. Even though the said technical solution well addresses the aforesaid problem about the product volume and contact resistance, some problems still exist. For example, the relays usually have to work in the environment where the temperature changes sharply, the air humidity changes sharply and it rains, snows and ices, and the ambient working environment is with moisture and water, for which this technical solution does not have a good sealing effect. The water will easily enter into the relay through the fuse inserting hole. As a result, various electronic components of the relay will be damaged and corroded for a long period, for which the relay could not work normally and even serious safety accidents could take place in use. At present, the sealing cover could also be adhered to the port of the fuse inserting hole through a sealant, and the fuse could be sealed into the fuse inserting hole. However, firstly, the fuse has to be replaced and the sealant has to be destroyed to separate the sealing cover from the port of the fuse inserting hole when the fuse is replaced. A new fuse can only be mounted after the old fuse is taken out, and the sealant has to be used for sealing and gluing, which is quite troublesome. Secondly, the automotive is in vibration in operation leading to a poor sealing and gluing effect over time. A gap occurs between the sealing cover and the port of the fuse inserting hole, which results in a poor sealing effect.